Electric connecting plug



June 10, 1941.

C. H. KOHNE ELECTRIC CONNECTING PLUG Filed Jan. 17, 1939 EIIIIIIE: Hill- 3nvento'r %M 14 1 M i attorney Patented June 10, 1941 UNITED, STATES OFF-ICE.

2,245,148 ELECTRIC CONNECTING PLUG Charles H. Kohne, Pittsburgh, Pa. Application January 17, 1939, Serial No. 251,349

1 Claim.

This invention relates to an electric connecting plug, f the n connection with an extension cord forjoining electrically operated appliances, such as lamps, sweepers, refrigerators, washers, irons, toasters, and the like, with the source of electrical supply.

Difficulty has been encountered with the conventional cord and plug set due to the severance and loosening of the conductors from screw and plug terminals, either from repeated handling or from material deterioration, with resultanthazardous short circuits.

Important objects and advantages of the pres-- ent invention are to provide an electric connecting plug of the character described, which will greatly reduce accidental disconnection of conductors and which will permit anyone to make simple interchangeable replacements when required, which is simple in its construction and arrangement, durable and eificient in its use, attractive in appearance, and economical in its manufacture, attachment, and maintenance.

With the foregoing and other objects in view which will appear asthe description proceeds, the invention resides in the novel construction, combination and arrangement of parts herein specifically described and illustrated in the accompanying drawing, but it is to be understood that changes in the form, proportions, and details of construction may be resorted to that come within the scope of'the claim hereunto appended.

In the drawing wherein like numerals of reference designate corresgxmding parts throughout the several views:

Figure 1 is a side view'of an electric connecting plug constructed in accordance with the invention.

Figure 2 is a longitudinal cross sectional view thereof.

Figure 3 is a forward end view of the improved p u of the plug on line 4-4, Figure 1. I

Figures 5 and 6 are, respectivelmlongitudinal, cross sectional and forward end views of a modified form of insulating core, embodying the present invention.

Referring in detail to the drawing, l denotes a hollow, cylindrical body providing a chamber 2. The latter has an open rear end, and theforward end thereof is closed by a forward end wall 3 forming an integral part of the body.

Figure 4 is a transverse, cross sectional View prong type commonly employed taching prongs or contact arms 4, adapted for the inserted engagement in the conventionbl type of associated receiving element well known in the art, project forwardly from the body end wall 3, and have their rear end portions embedded and permanently fixed in said end wall. Each of the arms 6 carries a flat contact plate 5, which is of considerable area and disposed at right angles to respective arms at the inner side of the body end wall. The surface of the contact plates 5 are preferably disposed slightly rearward of the plane of the surface of the inner side of the end wall.

' The chamber 2 is cylindrical, and a correspondingly-shaped insulating core 6 is removably mounted in the former. A pair of spaced flat contact plates 3 are embedded and permanently fixed in the forward end of the core. faces of the contact plates 1 are disposed slightly forward of the plane of the forward face of the core, and have areas commensurate to the areas of the contact plates 5,-with which latter they are adapted to make contacting engagement, when the, core is assembled in the body I. The core is formed with a longitudinally extending groove 8 for engaging a ridge 9 on the other suitable manner, and are side wall of the chamber to prevent rotationof said core in the latter and thereby assure the accurate contacting engagement of the contact plates I with thecontact plates 5.

The core 8 is maintained and secured in the body chamber 2, by a collar can III, which has a screw thread connecting engagement with the rear end of the body I. The collar cap is formed with a central, inwardly disposed boss ll engaging the rear end of the coreFwhereby the adjustment of the collar cap may be employed to forcibly maintain the contact plates 1 of the core in constant contacting engagement with the contact plates 5 of the body, as clearly illustrated inFigure 2. The peripheries of the body and collar cap are formed with knurled portions, respectively indicated at !2 and I3, for the obvious purpose of'facilitating the adjustments of the cap on said body.

The end of a conductor cord 14, of any conventional construction, is permanently embedded and secured in the insulating core 6, and the terminals l5 thereof are splayed and permanently connected with respective contact plates I, by means of welding, soldering, or in any likewise permanently embedded in the core.

The

A pair of parallel disposed, suitably spaced atthrough an aperture l6 provided therefor in the The surconnected end of the cord li extends and permanently secured in the rear endof the core 6, and likewise extends through the cap aperture IS. The pull member may be in the form of aspiral spring, as shown, or any other suitable, flexible pull device capable of serving as a pull element and of preventing the sharp flexing of the cord ll at the connection of the latter with the plug structure.

It will be apparent that the improved plug structure, embodying conductors permanently anchored in the 'core- 6 and virtually having conductors joined integral with the contact plates I, as herein set forth, will provide a cord and plug set of relatively prolonged life and greater efliciency.

"I'he'modified form of insulating core I8, illustrated in Figures and 6, differs from the core S in that the terminals IQ of the cord 20 are not permanently joined with the contact plates 2|, but are detachably secured to the latter by screws 22 in the. usual manner. The cord and terminals in this modified form are not permanently embedded in the core I8, and the latter is formed with suitable recesses to allow the attachment of the cord to the core,

cap III, are molded to shape andmay be constructed of any suitable, insulating composition material. Further, the contour of the body and cores may be varied'to provide a configuration adaptable for use to best meet any conditions found in practice.

or the detachment of the said cord from the latter. The body I, the cores 6, l8, and the collar The present invention provides a most durable and eiiicient device of itskind. which may be economically constructed and employed in the manner and for the purpose set forth.

What I claim is:

An electric connecting plug for a conductor cord comprising the combination of a hollow cylindrical body having an open rear end and being provided with a wall closing the forward end thereof, a pair of forwardly projecting. contact arms fixed in said wall and being" provided with fixed contact elements disposed at the innet side of said wall, an insulating core mounted in said body and being provided with a longitudinally extending groove, and a pair of contact members fixed to the forward end of said core and contacting with respective contact elements, a longitudinally extending ridge formed on the inner periphery 'of id body and engaging in said groove for assuring the alignment of said contact members with said contact elements, the

terminals of one end of said conductor cord being permanently embedded in said core and joined with respective-contact members, an a1 ertured cap having a screw thread connection with the a boss engaging the rear end of said core for maintaining and securing the latter in said body and a spiral spring surrounding the connected end portion of the conductor cord and projecting through said apertured cap and having its forward end embedded and permanently secured in saidvcore.

CHARLES H. KOHNE.

open end of said body and including 

